XRAY - Model racing cars

I just finished building my 2011 T3 and took it for a test drive. I am not a pro but I have 3 '07s, 1 '08 and now the T3. You can imagine how exited I was to build and run this car after scraping together the pennies to buy it.

I have experience with the Multi Diff in my '07, two ball diffs in the other '07s and the '08 is basically stock. I bought all these cars new so I have a decent amount of time on each one. With he '07s and '08 I can interchange parts so trouble shooting is a breeze.

I put together the T3, stock. I headed out to my local race lot with real excitement running through my veins. I am aware of the proper break-in procedure for ball diffs so my day was planned to be a nice easy get acquainted run. I have a Castle Creation 7700kv motor and the Mamba Max Pro ESC. I am running rubber slicks, stock shock springs, stock spur gear and a 22 tooth pinion. A very conservative setup. A Venom 5000Mah 40C Lipo 7.4volts.

Immeadiatley I noticed something wrong. I was new to running a solid front axle so I gave it some time and took it nice and easy. But something was wrong. So wrong that after halfway through the second battery i packed it up and headed home. I noticed i was not getting any diff action in the front, nothing. I took out the diff and popped of the plastic cover. This is what I saw:

File comment: This is the diff after 10 minutes of run time.

tranny3.jpg [ 216.55 KiB | Viewed 3789 times ]



The holes for the diff balls were mangled. The unit comes preassembled and did not show any signs of tightness or any problem. The balls have nothing to ride on except the plastic covers. It seems the diff rings are to small or... I don't know. A picture of the diff on the web site shows two seperate piece covers for each side. This tranny (an in the instruction book) shows only one piece covers for each side.

What on earth could have happened?

There is no way the diff washer (#305082 17x23x1) can be the same part for a 38 tooth pulley as it was for a 34 tooth pulley. I am confused. Please help.

Hi Ray, I cannot say I know what has gone wrong but that sure doesn't look like an XRAY Alu diff to me! I don't know what those teeth are that the picture is showing.

FYI the diff for 38T and 34T is exactly the same using the same parts except that the 38T pulley has a larger outer diameter (and more teeth) and the dust covers are larger to suit.

Yellowshark,
I appreciate the reply but the car was bought at a hobby shop with the box sealed. The diff was preassembled and packaged separately in an Xray parts bag.

I don't know what he aluminum balls were supposed to be riding up against but the diff cover I'm sure wasn't meant to be it.

Anyone else can recognize the problem?


Thanks.

BTW, I put the diff inside a roll of electrical tape so the entire part could be seen. That might be confusing to some people.
Thanks again.

It looks to me that the balls are located in the outer set of (oval) holes in the diff pulley, which is incorrect. They need to be on the inner ring of holes, sandwiched under the diff rings and output shafts.

Looks like a mis-build to me, and if it was like this out of the box, you should return the diff to the hobby shop/factory

HTH

bring it back to the LHS and try to get a new one from xray for free

............obviously return the diff if it is damaged (as I assume it must be), otherwise strip and rebuild

looks to me like its been slipping and melted

Even though something might be factory assembled, it usually pays to check that it's assembled correctly. It would also ba assembled by hand and people do make mistakes, especially when doing the same thing over and over. With no diff balls contacting the diff rings I doubt you would have had any diff action at all from the start.

Case in point with the ECS drive shafts as they're assembled without grease.

You say you've had it for a year, you won't get warranty as warranty is only good for the first 30 days.

Buy a new diff gear, rebuild the diff properly and go racing again.

Xray sent me the replacement parts so I'm back in business. I sure learned a lesson. When something comes preassembled you would think it was because they didn't want the user screwing it up. I never thought it could come screwed up.

Many thanks to the Xray team. Again, I picked a great car to drive. Now if i can only sell my '11 to pay for the '12 I just got in the mail!